This invention lies in the field of thermal joining of plastic pipe such as polyolefin. More particularly, it is concerned with a combination apparatus for fusing side wall plastic fittings to the walls of a pipe main.
It is well known in the art of joining plastic pipe and the like by facing the butt end of two pipes, heating the ends to a selected temperature until they become molten, and then pressing the two ends together. This will make a longitudinal joint which is as strong as the original pipe. It is also well known that the facing ends of the two pipes must be heated to a specific temperature and be pressed together with a selected force in order to make a perfect joint. Consequently, it is logical that there should be a force measuring means associated with any apparatus for joining two plastic pipe elements.
Furthermore, in the joining of smaller pipes to large pipes various sizes of sidewall fittings are required. Molded plastic fittings are available on the market, for attachment to main pipes of various medium and large diameters. Since the diameters and wall thicknesses of these attachments and pipes will vary considerably it is important to know what the force is at any moment between the two butting portions of the fitting and the main pipe.
Therefore, particularly for the assembly of sidewall fittings the force of application is critical. Although the strength of a man's arm forcing the two pipes together by means of a lever can be judged approximately, a precise representation of the force is desirable. This application provides a simplified portable apparatus for fusion of sidewall fitting, and provides a direct reading force gauge, that will precisely indicate the force being used at any instant to press the two parts together.